1. Field Of The Invention
The present invention pertains to toilet tanks and, more particularly, to devices for preventing and detecting leakage of water through flush valves of the toilet tanks between flush cycles.
2. Description Of The Prior Art
Most toilet tanks include a float movable with the water level in the tank during flush cycles to operate a water inlet valve to refill the tank upon lowering of the water from a predetermined level and to close the water inlet valve once the tank is refilled to the predetermined level. During flush cycles, operation of a flush lever unseats a flush valve in the tank causing the water in the tank to be released through a discharge opening, and the float descends in response to lowering of the water level from the predetermined level causing opening of the water inlet valve to refill the tank with closure of the flush valve. As the toilet tank is refilled, the float ascends in response to rising of the water level and, when the water level returns to the predetermined level, operates to close the water inlet valve and prevent further supply of water to the toilet tank. A problem exists where the water level in the tank drops from the predetermined water level not due to flushing but due to leakage, typically through the flush valve, between flush cycles in that the float operates to open the water inlet valve allowing water to flow into the tank to replace that lost through leakage. Where the leakage is continual, the float operates to keep the water inlet valve open such that water continually flows into the tank and through the discharge opening; however, the leakage can be sporadic or intermittent such that the float operates at unspecified times to open the water inlet valve. Both types of leakage commonly occur and are difficult to detect audibly and visually such that the leakage problem can remain undetected. In many cases, consumers are alerted to major, continual leakage only through drastically high water utility bills while insidious or sporadic leakage can remain unrecognized with consumers inadvertently absorbing inflated water utility costs of the leakage. In addition to a direct economic burden on consumers, the aggregate effect of water leakage through deficient flush valves of toilet tanks is the waste of untold gallons of water, an increasingly scarce resource.
Various devices have been proposed to prevent opening of water inlet valves of toilet tanks except when the flush levers are actuated such that refilling of the tanks between flush cycles is prevented when the water level drops due to leakage, and U.S. Pat. Nos. 4,901,377 to Weir, 4,843,657 to Orr, 3,095,577 to Clark, 2,841,169 to Martin et al, 265,709 to Sniffen and Great Britain Patent 488,402 are illustrative of such devices. Some of the disadvantages of prior art toilet tank leakage prevention devices are that the devices can not be easily retrofit to the many, diverse flush mechanisms and toilet tanks in use, the devices are structurally and functionally complex requiring numerous expensive components, the devices are not easily assembled on a common type of water inlet valve, i.e. the FLUIDMASTER type valve, found in existing toilet tanks, the devices are particularly susceptible to failure and malfunction, the devices do not limit the amount of water allowed to leak from the toilet tanks and the devices do not serve to promptly indicate or detect leakage.